Hyperbaric chambers



y 2, 1967 A. P BOEHMER 3,316,828

} HYPERBARIC CHAMBERS Filed Dec. 30, 1964 InvenZEr Qrzdrewffioe/zmer United States Patent 3,316,828 HYPERBARIC CHAMBERS Andrew P. Boehmer, llarrington, Ill., assignor to Borg- Warner Corporation, a corporation of Illinois Filed Dec. 30, 1964, Ser. No. 422,268 4 Claims. (Cl. 981.5)

This invention relates generally to pressure vessels, and more particularly to hyperbaric chambers especially adapted for use in medical techniques involving a process known as hyperbaric oxygenization.

In recent years, research into hyperbaric oxygenization has proved it to be a useful technique for delivering oxygen to vital organs and tissues when normal circulation or oxygen supply is impaired, and has utility in the treatment of certain circulatory diseases and for providing an environment for special surgical procedures.

The concept of hyperbaric oxygenization is relatively simple. A person to be treated is placed in a suitable pressure vessel and the air pressure within the vessel is increased several times the normal atmospheric pressure at sea level. While the patient is within the pressurized enclosure, pure oxygen is administered to the patient by mask, oxygen tent, or other suitable means. Because oxygen pressure at sea level is only about 150 mm. Hg, little O is normally dissolved in the plasma. However, if surrounding pressure is raised to three atmospheres and a patient is given 100% oxygen to breathe, the quantity dissolved in the blood rises 30 percent, most of it in the plasma. The result is a drenching of the patient with oxygen; the plasma becomes so saturated with 0 that it alone can oxygenate the tissues adequately, even without oxygen from the hemoglobin.

In cases where the blood supply is diminished, an adequate supply can be maintained to prevent tissue or organ damage. Similarly, treatment of gas gangrene bacilli, which thrives in an oxygen'free environment, shows considerable promise, as does treatment of carbon monoxide poisoning, the bends or caisson disease, certain forms of strokes and degenerative diseases of the blood vessels.

While the pressure vessel used in the conventional hyperbaric chamber comprises a structure having a relatively straight-forward design, certain requirements which are unique to its medical applications create problems in the construction of such chambers. For example, the air to be supplied to the chamber must be controlled at stabilized conditions to maintain a temperature of approximately 72 F. (dry bulb) when the ambient is between 70 F. and 80 F., and a relative humidity between 60 and 65%. Moreover, all of the air supply to the chamber must be treated by high quality filtration measures and continuously flowed through the chamber in such a way that recirculation is held to a minimum. This latter requirement involves a large number of air changes per hour and the avoidance of dead spaces which stall the free flow of air through the chamber. Re-circulation as referred to above means internal re-circulation. Under no circumstances, is the air exhausted from the chamber returned.

The conventional hyperbaric chamber is in the form of a spherical or elongated cylindrical shell, a circular crosssection being desirable to permit more even distribution of the pressure within the shell and avoid localized stress conditions. As a result, the working zone, i.e. the space in which the patient is treated and the surgical operations performed must be provided with a suitable floor or deck; otherwise, the bottom of the shell, due to its dished shape, would be impossible to work in.

Construction of the flooring has presented several problems. First of all, the pressure between working zone and space underneath the floor must be equalized to pre- 7 vent the flooring from buckling. Since the floor area in some chambers is in excess of 30 sq. ft, a presure differential of only 1 p.s.i. would be equivalent to a load of more than 20 tons. It can be appreciated that the most obvious way of handling this would be to provide perforations of openings through the floor to equalize this pressure. However, since the flooring and the bottom of the shell define a substantially dead air movement zone, it has been found that contaminated air, containing airborne bacteria and vapors, will sweep downwardly from the working zone into this substantially dead air space and be trapped, requiring removal of the floor and complete cleaning and sterilization thereof at frequent intervals. This dead air pocket also retards the free flow of air circulating within the chamber, and to the extent that it does circulate, puts an unnecessary load on the air-conditioning and filtration system.

The present invention is directed to the problem of preventing contaminated air from sweeping down and penetrating the space beneath the floor, while at the same time avoiding dead air pocket through which air cannot be continuously circulated and providing for the equalization of pressure on opposite sides of the floor. More specifically, the invention provides an improved hyperbaric chamber having an imperforate floor, permanently fixed and completely isolating the working zone above the floor from the dead space underneath, in combination with venting means for equalizing the pressure above and below the floor to prevent buckling thereof, and maintaining the space underneath the fioor filled with clean, filtered air at all times during the operation of the chamber.

It is therefore a principal object of the invention to provide an improved hyperbaric chamber which prevents contaminated air from flowing underneath the flooring, yet maintains an equal pressure above and below the floor to prevent buckling of said floor.

It is another object of the invention to provide an im proved hyperbaric chamber in which the dead space beneath the floor is always filled with filtered air during the operation of the chamber.

It is another object of the invention to provide means for preventing contaminated air within the working zone from backing up into the dead zone during the de-compression cycle.

It is still another object of the invention to provide a hyperbaric chamber in which the air conditioning load factor is limited to the chamber space actually utilized.

Additional objects and advantages will become apparent from the following detailed description taken in conjunction with the drawings wherein:

FIGURE 1 is an isometric view of a multi-unit hyperbaric chamber installation;

FIGURE 2 is a side elevational View of individual chambers; and

FIGURE 3 is a cross-sectional view taken along the plane of line 3-3 of FIGURE 2.

Referring to FIGURE 1, in which a typical multi-unit hospital installation is shown, this installation includes a plurality of individual hyperbaric chambers including a medical chamber A, in which patients requiring oxygen treatment or therapy may be placed, a second chamber B which may be used for performing surgical procedures under hyperbaric conditions, and a third chamber C which may be utilized as a re-compression and research chamber. Each of the chambers is divided into a working zone or section 10 and an air lock section 12 by a partition 13, said air lock section being provided to permit gradual adjustment to the pressure change. The lock sections 12 are interconnected by passages 14 having double doors 16 leading respectively into the air locks on either side thereof. Access to the chamber from the outside is provided by doors 18 opening into the air locks.

Referring now to FIGURE 2, in which chamber C is one of the G shown in a side elevational view, this chamber comprises an elongated shell 20 of generally cylindrical form, and end walls 21, 22, the latter having an access door 18. The chamber, as mentioned previously, i divided by a partition 13 into a working zone and an air lock 12, said partition having a door 16.

As pointed out in the preliminary remarks, an important aspect of the invention is the provision of a generally fiat, imperforate floor dividing and completely isolating the working zone 10 and air lock 12 above the floor from a dead zone or space 15 underneath the floor. The floor may be welded or otherwise fixed into position over suitable supporting structure (not shown), if required. As shown most clearly in FIGURE 3, the floor 26 extends across the lower portion of the shell in chordwise relation with regard to the cross-section. In the same manner, an imperforate ceiling 29 may also be provided, although this is an optional feature.

Conditioned and filtered air is delivered to the working zone and the air lock of each chamber through independently controlled supplies. This permits operating pressures in each chamber to be set at different levels in accordance with individual requirements, and allows the pressure within the air lock to be altered for pressure adjustment during controlled compression and de-compression of personnel (to avoid the bends) without changing the pressure in the adjacent working zone.

Although the description of the air supply is made with reference to the working zone of chamber C, it will be appreciated that similar supplies are also found in the other chambers, both in the working section and the air lock. As shown in FIGURE 3, filtered, conditioned air is delivered to the chamber from a suitable filtering and conditioning means (not shown) through conduit means or line 34 Line 30 extends through the shell and is interconnected with a conduit 31 which includes oneway check valve 32, and terminates in a distributor 33 of any conventional type, said distributor preferably in-' cluding means attenuating the noise caused by the inrushing air. The air is exhausted from a collector 34, also including a bafile or other arrangement for acoustical silencing and flows out of the shell through conduit 36. Regulating valves 37 and 38 control the supply of air admitted and exhausted.

As noted above, in order to prevent buckling of the floor, the pressure must be equalized on opposite sides thereof. Means for equalizing the pressure include a venting conduit having one end 40a communicating with the space 28 underneath the floor and the other end 40b communicating with a portion of the filtered air supply line 31. If a closed ceiling is employed, line 49 also includes an extension 41 opening into the space 39 defined between the ceiling 29 and the upper portion of the shell.

Operation When the chamber is pressurized, the supply and exhaust valve are set so as to permit the air to flow in at a faster rate than it flows out. Air is conducted through lines 30, 31 and valve 32 to the distributor 33 where it enters the chamber, and exhausted through collector 34 and line 36. The air supplied also flows through line 40 to the dead space 28 underneath the floor (and to the ceiling space 39. if an imperforate ceiling i used). The pressure above and below the floor will thus be equalized since both will always be at the same pressure as the inlet air.

During the de-compression phase of the chamber, valves 37 and 38 are set so as to exhaust air at least at a greater rate than the air is admitted to the chamber. During this phase of operation, the pressurized air within the dead space 28 fiows up through venting line at and through line 31 to the distributor 33. The one-way check valve 32 prevents air from within the working space from flowing back into the venting line 40 in the event the pressure 2 within the working space is ever higher than the pressure within the dead zone 28.

Another aspect of the invention concerns the reduction of the air conditioning load factor which is quite high because of the relatively small space, high intensity illumination and heat radiating equipment used in some of the chambers. Since the air cannot be re-circulated, and the air circulation rate in many chambers is in excess of 300 cubic feet per minute, the volume of filtered and conditioned air delivered into the chamber is considerable. Optimum economy of operation can be achieved by supplying the conditioned air only to the spaces requiring it. The solid floor (and ceiling) thu limits the volume of the space to be conditioned to that volume which is actually utilized. It will be appreciated that although the invention has been set forth with reference to a pressure vessel which is maintained, during operation thereof, at above atmosphere pressures, the principles involved could also be applicable to vacuum chambers where the problems are analogous. Also, while this invention has been described in connection with a certain specific embodiment thereof, it is to be understood that this is by way of illustration and not by way of limitation and the scope of this invention s defined solely by the appended claims which should be construed as broadly as the prior art will permit.

What is claimed is:

1. A hyperbaric chamber comprising a closed shell having generally circular cross section; a generally fiat, imperforate floor extending across the lower portion of said shell, said floor dividing the chamber into an upper zone above said floor and a lower zone beneath said floor; means for supplying air to said upper zone to provide super-atmospheric pressure conditions within said shell; and conduit means interconnecting said lower zone to said means for supplying air to equalize the pressure in said upper and lower zones; and check valve means associated with said air supply means to prevent air from flowing from said upper zone to said lower zone through said conduit means.

2. In a hyperbaric chamber of the type including a closed shell having a generally circular cross-section and means for supplying filtered air internally of said shell to provide super-atmospheric pressure therein, the improvement comprising a generally fiat, imperforate floor extending across the lower portion of said shell to divide said shell into an upper working zone and a lower dead air pace, said floor isolating said working zone from said dead air space to prevent contaminated air from being carried from said working zone into said dead air space; and means for directly venting said dead air space to said filtered air supply means to equalize the pressure above and below said floor; and check valve means associated with said filtered air supply means to prevent air from flowing from said upper zone to said lower zone through said conduit means.

3. A hyperbaric chamber comprising a closed, elongated, cylindrical shell, a generally flat, imperforate floor extending transversely across said shell to divide said shell into an upper space above said floor and a lower, dead air space beneath said floor; a partition dividing said upper space into a working zone and an air lock; means for continuously circulating filtered air through said working zone, said means including an air inlet conduit, a distributor, a collector, and an exhaust conduit; venting conduit means interconnecting said dead air space below said floor to said air inlet conduit; and a check valve between said distributor and the point of connection between said air inlet conduit and said venting conduit means to prevent air within the working zone from flowing to said dead air space through said venting conduit means.

4. A chamber as defined in claim 3, including an imperforate ceiling defining a second dead air space between said ceiling and the upper portion of said shell;

5 6 and conduit means interconnecting said second dead =air 1,224,180 5/1917 Lake 128--204 space with said air inlet conduit. 1,471,144 10/1923 Cunningham 61-83 X 2,373,333 4/1945 St. Onge 128-204 X References Cited by the Examiner UNITED STATES PATENTS 5 RICHARD A. GAUDET, Primary Examiner.

Re. 23,913 12/1954 Baak 98--1.5 K. L. HOWELL, Assistant Examiner. 

1. A HYPERBARIC CHAMBER COMPRISING A CLOSED SHELL HAVING GENERALLY CIRCULAR CROSS SECTION; A GENERALLY FLAT, IMPERFORATE FLOOR EXTENDING ACROSS THE LOWER PORTION OF SAID SHELL, SAID FLOOR DIVIDING THE CHAMBER INTO AN UPPER ZONE ABOVE SAID FLOOR AND A LOWER ZONE BENEATH SAID FLOOR; MEANS FOR SUPPLYING AIR TO SAID UPPER ZONE TO PROVIDE SUPER-ATMOSPHERIC PRESSURE CONDITIONS WITHIN SAID SHELL; AND CONDUIT MEANS INTERCONNECTING SAID LOWER ZONE TO SAID MEANS FOR SUPPLYING AIR TO EQUALIZE THE PRESSURE IN SAID UPPER AND LOWER ZONES; AND CHECK VALVE MEANS ASSOCIATED WITH SAID AIR SUPPLY MEANS TO PREVENT AIR FROM FLOWING FROM SAID UPPER ZONE TO SAID LOWER ZONE THROUGH SAID CONDUIT MEANS. 